Frey's Syndrome

Frey’s Syndrome is a syndrome that includes sweating while eating (gustatory sweating) and facial flushing. It is caused by injury to a nerve, called the auriculotemporal nerve, typically after surgical trauma to the parotid gland. This nerve, when it heals, reattaches to sweat glands instead of the original salivary gland (which had been removed during surgery).

Causes of Frey’s Syndrome #

• Frey’s syndrome often results as a complication of surgeries of or near the parotid gland or due to injury to the auriculotemporal nerve, which passes through the parotid gland in the early part of its course.

• The auriculotemporal branch of the mandibular branch (V3) of the trigeminal nerve carries parasympathetic fibers to the parotid salivary gland and sympathetic fibers to the sweat glands of the scalp.

• As a result of severance and inappropriate regeneration, the parasympathetic nerve fibers may switch course to a sympathetic response, resulting in gustatory sweating or sweating in the anticipation of eating, instead of the normal salivary response.

• It is often seen with patients who have undergone endoscopic thoracic sympathectomy, a surgical procedure wherein part of the sympathetic trunk is cut or clamped to treat sweating of the hands or blushing.

• The subsequent regeneration or nerve sprouting leads to abnormal sweating and salivation.

• It can also include discharge from the nose when smelling certain food.

• Rarely, Frey’s syndrome can result from causes other than surgery, including accidental trauma, local infections, sympathetic dysfunction and pathologic lesions within the parotid gland.

• An example of such rare trauma or localized infection can be seen in situations where a hair follicle has become ingrown, and is causing trauma or localized infection near or over one of the branches of the auriculotemporal nerve.

Symptoms of Frey’s Syndrome #

• Signs and symptoms include erythema (redness or flushing) and sweating in the cutaneous distribution of the auriculotemporal nerve, usually in response to gustatory stimuli.

• There is sometimes pain in the same area, often burning in nature.

• Between attacks of pain there may be numbness or other altered sensations (anesthesia or paresthesia).

• This is sometimes termed ‘gustatory neuralgia’.

Diagnosis of Frey’s Syndrome #

• The diagnosis of Frey’s Syndrome is usually as simple as talking to and examining the patient.

• An additional test that can be used to outlined the facial area is called the minor iodine and starch test.

• In this test, iodine is applied to the symptomatic side of the face.

• After it dries, cornstarch is applied. When the patient sweats (with food stimulus), the affected area gets dark.

Treatment of Frey’s Syndrome #

• For patients with more severe and bothersome symptoms, there are several options for treatment.

• For permanent treatment, reconstructive surgery is the only option.

• In experienced hands, surgery has the added benefit of being able to reduce facial scars from incisions and correct facial deformities from the initial surgery.

• However, most surgeons are not capable of performing a true reconstruction that both prevents Frey’s syndrome and treats the facial deformity from parotidectomy.

Medical treatments include:

• Topical anticholinergic ointments (scopolamine, glycopyrolate)

• Topical anti-perspirants (deodorant)

• Topical α agonist (clonidine)

• Botulinum toxin injections

Botulinum toxin appears to be the easiest and safest method. It provides the longest period of symptom relief with the lowest complications.

However, none of these treatments allow a definitive cure, relief is only temporary.